Health disparities among minority groups in the United States are pervasive. Although it is widely accepted that health communication directed toward these groups should be culturally appropriate or culturally sensitive, little empirical work has been directed toward examining what aspects of cultural sensitivity are effective. This study aims to advance the theoretical understanding of which aspects of cultural sensitivity influence the perception and understanding of health messages. This understanding will improve the effectiveness of health communication targeting minorities. Even though the current study focuses on oral health in the Mexican-American community, with further study to generalize the findings, this work has the potential to impact the effectiveness of any sort of health communication (e.g., diet, diabetes prevention, or breast cancer screening) targeting a variety of health contexts and ethnic/cultural groups. Mexican-Americans are the largest and fastest growing segment of a fast growing Hispanic population. Mexican-Americans have the lowest levels of dentist visits (Wall & Brown, 2004) and their children are more likely to have untreated caries (Healthy People, 2010) and to have never visited a dentist than any other group (Scott & Simile, 2005). Written oral health messages containing information about caries formation and prevention in children will be developed in conjunction with consultants from two National Institute of Dental and Craniofacial Research funded centers addressing oral health disparities. The messages will target Spanish speaking mothers of young children. Researchers have theorized two dimensions of cultural sensitivity: surface structure (e.g., images and graphics) and deep structure (e.g., cultural values and beliefs) (Resnicow, Braithwaite, Ahluwalia, & Baranowski, 1999). Using recent work on Mexican-American beliefs about oral health and caries etiology (e.g., Hoeft, Barker & Masterson, 2010), the cultural appropriateness (high vs. low) of surface and deep structure will be manipulated to give four different messages in a 2x2 experimental design allowing the investigation of the effectiveness of each type of cultural appropriateness and the interaction. Participants will be 300 Spanish speaking Mexican-American mothers who will be randomly assigned to one of the four conditions. Half of the participants will get a pretest to assess their initial knowledge and beliefs. All participants will receive a posttest assessing knowledge, beliefs, intentions, and perceptions of the message. In addition, 20 participants from each condition will be randomly chosen to have an in-depth interview to better understand the effects of the messages. Learning which messages are effective, and why, will improve oral health communication to Mexican-American mothers. With further research, the theoretical and practical gains made in the proposed research could be generalized to impact other types of oral health communication for Mexican-Americans and further to many types of health communication for ethnic/cultural minorities. Ultimately, understanding cultural sensitivity will help in the tailoring of health messages delivered on the internet. PUBLIC HEALTH RELEVANCE: This research will improve the effectiveness of written oral health messages targeting Spanish speaking Mexican-American mothers by exploring different aspects of cultural sensitivity. Results may impact the oral health of Mexican-American children as well as, with more research, generalize to a wide range of health messages targeting a variety of minorities.